"It's a tough existence for the sea lions to survive, let alone breed at the bottom of the cliffs," Mr Holman said.

The 3D models of the cliffs would allow parks management to study how the colonies are changing over time and how they fit with the population trends.

Hunted almost to extinction

It is believed that in the early 1800s the Australian sea lion, or Neophoca cinerea, was nearly hunted to extinction in some areas by commercial sealers, including around Bass Strait and off Albany in Western Australia.

Now the pinnipeds are only found in colonies from The Pages off South Australia to the Houtman Abrolhos in WA but the populations have not recovered from sealing and were listed internationally as endangered in 2008.

"Unfortunately they're not tracking too well," Mr Holman said.

"The latest state-wide population survey we did showed a 78 per cent decline over three generations, which is significant.

"There's been an overlap of fishing effort with the sea lions' foraging grounds so there's been an historical incidental bycatch of the animals.

"Unfortunately they only breed every 17 and a half months so they don't breed every year so when there are fatalities through bycatch, and if that's gone on for a period of time, then they're going to recover really slowly."

Population still declining

Department of Environment research lists fisheries bycatch as the primary threat, as well as demersal gillnet fishing for sharks, rock lobster pots, and entanglement in marine debris.

Among the secondary threats listed were marine fish aquaculture, including loss of habitat and entanglement as well as direct killing, disease, pollution, oil spills and noise, particularly from seismic surveys, construction, or marine operations.

"There has been a lot of work done to minimise the interactions between the fisheries and the animals so we're sort of hoping that pretty soon we'll see a response in the pup production," Mr Holman said.

"We mainly pups in a survey so the last survey state-wide, which we did 2014/2015, there were just over 2,200 pups.

"[That's] down from 2,900 pups between six or seven years earlier so you can see that the pup numbers are declining across the state."